LED devices are semiconductor photonic devices that emit light when a voltage is applied. LED devices have increasingly gained popularity due to favorable characteristics such as small device size, long lifetime, efficient energy consumption, and good durability and reliability. In recent years, LED devices have been deployed in various applications, including indicators, light sensors, traffic lights, broadband data transmission, and illumination devices. For example, LED devices are often used in illumination devices provided to replace conventional incandescent light bulbs, such as those used in a typical lamp. These illumination devices require a relatively wide amount of light distribution, similar to that provided by conventional incandescent light bulbs. However, conventional LED devices may have some limitations in that regard, because light emitted from the LED devices is usually distributed in a relatively small angle, which provides a narrow angle of light and is dissimilar to natural illumination or some types of incandescent illumination devices. As such, conventional LED illumination devices may not be able to offer a true replacement for incandescent illumination devices.
Therefore, while conventional LED illumination devices are generally adequate for their intended purposes, they have not been entirely satisfactory in every aspect. It is desired to provide an LED illumination device that distributes light in a relatively wide angle, similar to that of an incandescent light bulb.